Rainbow Electronics MAX5661 - Manual (Page 25)

MAX5661
Single 16-Bit DAC with Current and Voltage
Outputs for Industrial Analog Output Modules
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Input Register (Read/Write)
Write to the input register to store the DAC code.
Transfer the value written to the input register to the
DAC register by pulling the LDAC input low or by writ-
ing to the load DAC register (0x05). Set the command
byte to 0x03 to write to the input register. Set the com-
mand byte to 0x07 to read from the input register. Bits
D15–D0 contain the straight binary data (see Table 5).
DAC Register (Read/Write)
Write to the DAC register to update the OUTV and OUTI
outputs after CS returns high. Set the command byte to
0x04 to write to the DAC register. Set the command
byte to 0x08 to read from the DAC register. Bits
D15–D0 contain the straight binary data (see Table 6).
Load DAC Register (Write)
Write to the load DAC register to transfer the input reg-
ister data to the DAC register and update the DAC out-
put. Set the command byte to 0x05 to write to the load
DAC register. Bits D15–D0 are don’t-care bits.
Clear Register (Read/Write)
Write to the clear register to set the DAC output value
when the CLR hardware input is pulled low (forcing the
MAX5661 into the clear state). Set the command byte to
0x06 to write to the clear register. Set the command
byte to 0x09 to read the clear register. Bits D15–D0
contain the straight binary data (see Table 7).
No Operation
Set the command byte to 0x0F or 0x00 to perform a no-
operation command. After writing the command byte
and 2 data bytes (16 don’t-care bits), read out the shift
register’s contents on the following 24-bit cycle.
BIT NAME DATA BIT RESET STATE FUNCTION
IN15–IN0 D15–D0
0000 0000 0000 0000
(unipolar/current)
1000 0000 0000 0000
(bipolar)
IN15 is the MSB and IN0 is the LSB. Data format is straight binary.
Table 5. Input Register (Read/Write)
BIT NAME DATA BIT RESET STATE FUNCTION
DAC15–DAC0 D15–D0
0000 0000 0000 0000
(unipolar/current)
0000 0000 0000 0000
(bipolar)
DAC15 is the MSB and DAC0 is the LSB. Data format is straight
binary.
Table 6. DAC Register (Read/Write)
BIT NAME DATA BIT RESET STATE FUNCTION
CLR15–CLR0 D15–D0
0000 0000 0000 0000
(unipolar/current)
1000 0000 0000 0000
(bipolar)
CLR15 is the MSB and CLR0 is the LSB. Data format is straight
binary.
Table 7. Clear Register (Read/Write)
BIT NAME DATA BIT RESET STATE FUNCTION
FS_EN +
FS_BIT9–
FS_BIT0
D9–D0 0000 0000 0000 0000
FS_EN (D15) enables the full-scale output adjustment feature. D9
is the MSB and D0 is the LSB. D9 is straight binary, D8–D0 are
inverted binary.
Table 8. Full-Scale Output Trim Register (Write)